Heated revolving drum

ABSTRACT

The invention concerns an industrial drying appliance which may be used in the paper or textile industries, or to dry substances in suspension, such as muds. A revolving drum contains internal means of heating, consisting of at least one combustion chamber connected with sources supplying fuel and oxygen, and producing a flame in the combustion chamber, and at least one passage reaching from the central axis of the drum to the drum-wall, and opening into a pipe to remove fumes.

United States Patent 1 1 Bourrel' et -al.

HEATED REVOLVING DRUM inventors: Jean Bourrel, Montreulil; Maurice Remond, Lescar; Noel Potie, Gelos;

Guy Lagacherie', Grenoble, all of 'France Assignees: Societe Nationale Des Gas Du Sud- Quest, Pau; Compagnie Des Fours lndustriels, Montreuil, France Filed: Feb. 2,1971

Appl. No.: 11 1 ,886

Foreign Application Priority Data Feb. 3, 1970 France .7003703 34/124 Int. ,..F27b 7/00 Field of Search; ..432/228; 34/119,

[451 Apr. 24, 1973 [56] References Cited UN lTED STATES PATENTS 2,225,166 12/1940 Frby: 3 1/119 x 2,362,947 1 1/1944 Sullivan ..34/124 UX 7 2,987,305 6/1961 Calhoun, Jr. .....34/124 X 3,452,967 7/1969 Durand ..263/6 C Primary Examiner-John J. Camby Alta-[slant Examiner--Henry C. Yuen Att0rney-H0lc0mbe, Wetherill & Brisebois ABSTRACT The invention concerns an industrial drying appliance which may be used in the paper or textile industries, or to dry substances in suspension, such as muds.

A revolving drum contains internal means of heating, consisting of at least one combustion chamber connected with sources supplying fuel and oxygen, and producing a flame in the combustion chamber, and at least one passage reaching from the central axis of the drum to the drum-Wall, and opening into a pipe to remove fumes.

8 Claims, 2'Drawing Figures HEATED RsvoLvrNc DRUM The present invention concerns a heated revolving drum, the whole surface of which is at a homogeneous temperature.

' ensure adequate thermal inertia to make the surface temperature homogeneous, since most of the heat is transferred by conduction. Second, water condenses on the roller walls during operation, involving the risk of making them heavier if the condensation removal system is inadequate. The superstructures therefore have to be very strong, and are consequently heavy and expensive, raising the cost of the installation further.

Third, heating with steam under pressure almost inevitably involves the need for a boiler, another factor increasing installation costs.

Finallyfenergy consumption is very high, both to drive the rollers and to generate steam pressure.

Another existing system involves providing a heatconveying fluid inside drying rollers; this fluid is kept in contact with the roller wall and transmits to it,

, uniformly, heat provided by some means of heating.

The main drawback of the presence of this inter-v mediate fluid is the additional energy required to keep it revolving.

Other rollers contain an internal heating system such as a combustion chamber inside the roller, the heat from the combustion gas being transmitted directly to the cylinder wall or to an intermediate fluid. The disadvantage of such systems, where the heating fluid, such as gas produced by combustion, fills the whole inside of the roller is that steps need to be taken to ensure that all the joints existing at the points of attachment of the roller are tight; another drawback is that symmetrical supply, which is sometimes necessary, is impossible. Furthermore, where deflectors are placed in a zig-zag arrangement inside the cylinder, in order to make the heating fluid follow a particular course, extra energy is required to make these deflectors in the path of the gas revolve with the roller.- 7

The present invention eliminates these drawbacks, as well as providing other advantages, such as increasing the operating flexibility of the installation.

in this invention, a heated drum, mounted so as to rotate on its axis and made to revolve, contains an internal system of heating, which remains immobile when the installation is inoperation, and which consists of at least one combustion chamber, connected with supplies offuel and oxygen, and at least one tubular passage extending across the space between the axis of the drum and the drum wall, one end being connected to the combustion chamber and the other to a pipe to remove'the fumes.

One of the main advantages of this invention is that, because of the placing of the combustion chamber along the inner axis of the drum, and the arrangement of pipes through which the combustion gas passes, only the outer wall of the drum rotates, all the other components remaining fixed. In addition, this method eliminates any direct contact between the combustion gas and the walls and sides of the cylinder, without the need for the use of a double casing for the intermediate fluid, or for devices to ensure perfect tightness.

According to one embodiment of the present invention, the tubular passage contains bends, so as to set up turbulence, which varies depending on the heat transfer required.

Partial masking devices may also be used to reduce excess radiations.

These pipes may be hair-pin-shaped, their arms parallel to the drum axis and the bends situated close to the edges of the drum.

According to one embodiment of the present invention, the drum contains two burners, one at each end of the drum and along its axis; each burner opens into a series of three hair-pin-shaped pipes, at an angle of to one another.

According to another embodiment of the present invention, the drum has a spiral pipe, the pitch of which is selected in each individual case to provide the heat flux required.

According to yet another embodiment of the invention, there are two burners, one at each end of the drum and along its axis, each opening into pipes with the same pitch but with reverse fluxes.

The burners are fed with products such as combustible gas and air, or domestic fuel-oil and air.

There may be a fume-removal pipe round each of the burners at each end of the drum; this may be in the form of a smoke-box. This arrangement has the advantage of being of simple construction, and of being easily assembled, because of the compactness of the unit containing the burner and smoke-box.

It will be easier to understand the invention from the following description, and the accompanying drawings.

FIG. 1 showsa lengthwise vertical cross-section of a drum designed in accordance with the present invention.

FIG. 2 shows two spiral pipes.

In FIG. 1, a large-diameter drum 1 revolves on two bearings 2, inside which combustion chambers 9 and 9a and smoke-boxes or exhaust manifold 13 are fixed concentrically on bases 14; in the embodiment of the invention described here, the smoke-boxes insulate the bearings from the combustion chambers.

The combustion chambers are fed with fuel and the oxygen-supplying agent through the inlets 7 and 8, and the resulting gas escapes at the required temperature into the tubular or radiating passages 11 and 11a, which are hair-pin-shaped, and the bends in which, 10 and 10a, 12 and 12a, allow the desired effect to be obtained; straight lengths are slightly shorter I than the lendth of the drum and are situated at a uniform, fairly short distance from the wall of the drum, about 10 centimeters for instance. Combustion extends overpart of the lengthof these pipes, and the bends set up turbulence, thus creating higher production of calories at the points where they occur, compensating for the heatlosses at the ends of the drum.

In the installation involved here, the two combustion chambers 9 face each other, and are held by-a rigid unit 14, while stays 16 support the pipes through which the hot gas passes.

' The calories conveyed by the gas fumes can be recuperated from the smoke-boxes l3, and used to increase the drying power of the installation, by forced convection over the material being dried.

In the case described here, the cylinder is supported by roller-wheels 3 and3a, rotating on their axes 4 and 4a. Theseaxles are driven by the variable-speed reducing-gear motor unit 17-18.

Masks 15, attached to the smoke-boxes, for instance, can ,preventexcessive heat from being transmitted to the drunrwally FIG. 2 shows another set of-radiating pipes, spiral in form. One pipe, 21, with a coupling 20 and an end 23, can be placed inside the drum 1, taking the place and performing the functions of the hair-pin-shaped pipe -11-12. The other pipe, 22, with the same pitch as 21 but with reverse flux, may be fixed to the second combustion chamber, taking the place and performing the functions of the pipe Illa-I 1a-I2a.

The drum according to the present invention operates as follows.

Gas and air are fed in, in given. proportions, through the inlets 8 and 7 respectively, and combustion of the resulting mixture is brought about by some known method, in the chambers 9 and 9a.-The gas produced by this combustion at'high temperature circulates in thepipes l 1 and 1 1a There are six of these pipes, three connected to each chamber and set at an angle of 60 to one another, so that the radiation from them affects the whole inside surface of the drum. It has been found that the temperature along a generating line on the drum is uniform. This is because the heat-loss effect at the edges of the drum has been compensated for by a greater heat flux than in the central section,.by means of the greater amount of heat emitted at the bends 10, 10a, 12 and 12a. The rotation of the drum also ensure homogeneityof temperature in all sections.

' heat emitted by them counterbalances heat losses, both longitudinally and transversely.

Naturally, the invention is not confined to the detailed embodiments described above for example, the length of the pipes can be adjusted in relation to the length of the cylinder, so as to alter the distance between the bends 12 and the edge of the drum, and vary the number of calories emitted at the ends of the drum.

What we claim is 1.A revolving heated drum mounted for rotationon its own axis and supported for rotation on a pair of bearing members provided at opposite ends of said drum,

means defining a stationary combustion chamber extending axially within said drum, 1 stationary means defining an exhaust duct at one end of said drum,

and means defining a tubular passage extending from said combustion chamber across the space between the axis of the drum and the drum wall to said exhaust passage.

'2. A heated drum in accordance with claim l, in which at least part of said tubular passage runs at a uniform distance from the drum axis.

3. A heated drum in accordance with claim 2,.in which the tubular passage'is U-shaped, with the arms parallel to the axis of the drum. I y

4. A heated drum in accordance with claim 2, in which said tubular passage is spiral in shape, with the same axis as said drum..

5. A heated drum as claimed in claim 1 in which there are a plurality of said tubular passages placed at equal angles around the drum.

6. A heated drum as claimed in claim-5 containing two of said combustion chambers along the axis of the drum, one at each end of the drum and each connected to one of said tubular passages.

7. A heated drum in accordance with claim 5, in which said exhaust duct comprises an exhaust manifold positioned concentrically around the combustion chamber at one end of the drum, and connected to a plurality of said tubular passages.

8. A heated drum in accordance with claim 6 in which said tubular passages comprise two spiral pipes, with 'thesame pitch mounted around the drum axis, one being connected to each of saidcombustion chambers at the end of the drum. r

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3.729.180 Dated April 2 4. 197? Inventor) JEAN BOURREL, MAURICE REMOND NOEL POTIE 8: GUY

' LAGACHERIE It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

[75] Inventors: Jean Bourrel, Montreuil; Maurice Remond,

' Les car; Noel Potie Gelos; Guy Lagacherie,

Grenoble, all of France [73] Assignees Societe Nationals Des Ga Du Sud-Quest,

Paris, France and Gompagnie Des Fours Industries, Montreuil, France Signed and sealed this 2nd day of April 1971;,

(SEAL) Attest:

EDWARD M.FLETCHER,J'R. C. MARSHALL DANN Attesting Officer Commissioner of Patents =ORM P0-105O (10- 9) uscoMM-Dc 60376-P69 U. 5 GOVERNMENT PRINTING OFFICE [Ill O-JG-SSI, 

1. A revolving heated drum mounted for rotation on its own axis and supported for rotation on a pair of bearing members provided at opposite ends of said drum, means defining a stationary combustion chamber extending axially within said drum, stationary means defining an exhaust duct at one end of said drum, and means defining a tubular passage extending from said combustion chamber across the space between the axis of the drum and the drum wall to said exhaust passage.
 2. A heated drum in accordance with claim 1, in which at least part of said tubular passage runs at a uniform distance from the drum axis.
 3. A heated drum in accordance with claim 2, in which the tubular passage is U-shaped, with the arms parallel to the axis of the drum.
 4. A heated drum in accordance with claim 2, in which said tubular passage is spiral in shape, with the same axis as said drum.
 5. A heated drum as claimed in claim 1 in which there are a plurality of said tubular passages placed at equal angles around the drum.
 6. A heated drum as claimed in claim 5 containing two of said combustion chambers along the axis of the drum, one at each end of the drum and each connected to one of said tubular passages.
 7. A heated drum in accordance with claim 5, in which said exhaust duct comprises an exhaust manifold positioned concentrically around the combustion chamber at one end of the drum, and connected to a plurality of said tubular passages.
 8. A heated drum in accordance with claim 6 in which said tubular passages comprise two spiral pipes, with the same pitch mounTed around the drum axis, one being connected to each of said combustion chambers at the end of the drum. 